NEWBURYPORT — Deer ticks have been appearing in huge numbers throughout the region, raising concerns about Lyme disease.

All along the East Coast, health experts have seen a sudden and dramatic increase in ticks.

"Just in the past week or two, we have seen an explosion in deer ticks," said Dr. Heidi Bassler, medical director of the Veterinary Center of Greater Newburyport.

The unusually warm weather and record-setting rains have helped bolster the tick population. Hospitals, such as Addison-Gilbert in Gloucester, have experienced a surge in tick bite cases. Normally, the hospital sees one or two cases per day; now it is seeing eight or 10.

There are two different kinds of ticks that are predominant in the region. Dog ticks are about the size of a pencil eraser; deer ticks, the more dangerous species, are closer to the size of a pen point.

With a single bite, deer ticks can transmit Lyme disease, symptoms of which include a debilitating complex of fever, headache, fatigue and depression, and two other illnesses of similar symptoms.

Ticks are mostly found in woods and fields. High grass, including dune grass, is one of their favored habitats.

"We started seeing more and more ticks in the field," said Frank Drauszewski, deputy refuge manager at the Parker River Wildlife Refuge. "They are really active this year."

Prevention of Lyme disease is key. By spotting and removing ticks as soon as possible, the risk of Lyme is minimized. By removing an embedded tick within 24 hours of being bit, the risk of transmission is significantly reduced, Drauszewski said.

Experts recommend checking children and pets after outdoor activity.

Treatment is most effective in the early stages of the disease. Antibiotics are very effective against Lyme disease. Late detection of Lyme disease can result in more serious, lasting symptoms.

A circular skin rash often occurs around the bite. If untreated, Lyme disease can affect joints, the heart and the central nervous system.

Unlike with other diseases, exposure to Lyme does not lead to immunity, Bassler said.

Exposure to ticks can be avoided by tucking in clothing to cover exposed skin and applying repellent on outer layers of clothing. Wearing light-colored clothing can make it easier to spot the tiny arachnids. It is best to give pets monthly applications of tick control medication. Bassler warned that with a two-year life cycle, ticks are a year-round concern for pets.

The federal Centers for Disease Control considers the East Coast from southern Maine to northern Maryland a high risk area for Lyme. The disease is named after Old Lyme, Conn., after an outbreak of human Lyme disease in 1975.